Ultramicroscopic changes in the parathyroid glands and thymus after immunostimulation in rats

Abstract

Background. The burden of immunodeficiency and infectious diseases is rapidly increasing worldwide. Thus, it becomes necessary to find effective and affordable immunomodulatory drugs that may modify the response of the immune system. Objectives. To investigate ultramicroscopic changes that occur in parathyroid glands and thymus of male rats after administration of the immunomodulatory agent imunofan. Methods. Thirty-six WAG matured male rats were divided randomly into two groups. The first group received imunofan in a dosage of 0.7 mg/kg animal body weight by intramuscular injection. Rodents were sacrificed on the 3rd and 30th day after injection and specimens were dissected out and processed for electron microscopy. The second group served as control and was provided 0.9% soluble sodium chloride. Results. The results showed that imunofan exposure caused marked ultramicroscopic changes in parathyroid glands and thymus of rats. On the 3rd day after injection, the amount of the active chief cells significantly increases. A significantly increased number of secretory granules is recognized as the ultrastructural hallmark of chief cells change. Thymus in this term of imunofan administration showed no significant ultrastructural changes in comparison to control group. On the 30th day after the administration, the examination revealed that all the glands of the experimental rats have big amounts of active cells with well-developed secretory apparatus. Floccular or particulate material was observed in the enlarged intercellular spaces surrounded by three or more chief cells. A significant amount of the secretory granules as the material might be excreted by exocytosis into the intercellular spaces. Electron microscopy of thymus revealed that imunofan injection causes changes in organ as a result of the activation of cell-mediated and antibody-mediated immunity on 30th day. Apparently, it also causes temporary delay of age-related thymic involution. Conclusion. The dynamics of changes in the electronic microscopic structure of rats’ parathyroid glands and thymus indicates a high degree of organs reactivity in response to immunotropic drug administration.